Rabble for rotary hearth furnace

ABSTRACT

A fluid cooled rabble construction comprising a plurality of conduits extending along the surface of the rabble. The conduits provide a passageway which is in the nature of a circuitous path and a suitable coolant is circulated therethrough to effect a cooling of the rabble. The rabble may comprise a box-like element formed of steel or the like to which the conduits are secured or the rabble may comprise a structure composed entirely of a suitable refractory or a combination of a refractory and a steel face and edges.

United States Patent Middleton et al.

RABBLE FOR ROTARY HEARTH FURNACE Horace Middleton; Frank Tominc, both ofRock Springs, Wyo.

Inventors:

Assignee:

Filed:

Appl. No.:

Salem Corporation, Pittsburgh, Pa.

Nov. 29, 1972 References Cited UNITED STATES PATENTS 6/1973 Oleszko432/235 10/1969 Kemmerer, .lr. 201/33 6/1969 Allred 432/124 5/1973A1lred.... 202/218 4/1903 Edwards 432/139 2/1965 Brou'gh 432/234 Jan.29, 1974 1,825,947 10/1931 Fowler et al 432/139 1,599,467 9/1926 Graves432/139 2,376,177 5/1945 Nichols, Jr 432/235 3,594,287 7/1971 Allred432/85 2,187,201 1/1940 Hartley et a1 ll0/l2 2,483,592 10/1949 Nicholset al 432/235 3,419,254 12/1968 Von Dreusche, Jr.. 432/235 3,226,10112/1965 Balaz et a1. 432/234 [Ill 1 Ill 1L IL Primary Examiner-John J.Camby Assistant Examiner-Henry C. Yuen [5 7] ABSTRACT A fluid cooledrabble construction comprising a plurality of conduits extending alongthe surface of the rabble. The conduits provide a passageway which is inthe nature of a circuitous path and a suitable coolant is circulatedtherethrough to effect a cooling of the rabble. The rabble may comprisea box-like element formed of steel or the like to which the conduits aresecured or the rabble may comprise a structure composed entirely of asuitable refractory or a combination of a refractory and a steel faceand edges.

,20 Claims, 13 Drawing Figures PATENTED JAN 2.9 1974 SHEET 2 0F 4PATENTED JAN 2 9 I974 ,sum 3 or 4 PATENTEDJAHZQIW 8; 788.800 sum u or 4RABBLE-EOR ROTARY I-IEA'RTH FURNACE BACKGROUND'OF THE INVENTION Rabblesare commonly employed-in various types of furnaces for effectinga turnover andadvance of the materials being treated in suchfurnaces. Usuallysuch furnaces comprise astationary roof'and a moving or rotating hearthmounted therebelow. Materials to be processed withinisuch a furnace areusually, fedontothe hearth in any knownmanner and as the hearth moveswithin the furnace, roof orotherwise supportedrabbles engage thematerials thereorito effect-a turnover of the materials and in. someinstances, the rabbles. are also used. to-advance themater ials from;the point of entry into the furnace to a point'of exit therefrom, As canbe appreciated, the employmenti of rabbles in a furnace foraccomplishing: these results. pose some problems. One such problem. isto, construct a rabble in such a manner as to. enable the same to. beeffectively em ployed in furnace structures whereini guite frequentlythe temperature therein exceed 2,50,0fF. Another problem presented is toprovide for; the elimination of the erosive actionof the materialson thehearth. against the material employed in the formation of the rabble.Still another problem presented is to, effect as large a cooling areafor the rabble as is permissable consider ing the physical dimensions ofthe rabble, such as the height thereof. the wall thickness of therabble, width,

BIC.

With the above in mind it is the primary object of the invention toconstruct a rabble with Coolant passageways associated therewith so asto obviate the deterioration of the components of the rabble when thesame is exposed to high temperatures.

Another object ofthe invention is to form a rabble of a suitablerefractory material with coolant conducting passage-ways extendingtherein whereby the transfer of heat into the rabble walls andpassageways therein is minimized.

Another object of the invention is to construct a rabble of a suitablerefractory material with coolant conducting passageways extendingtherein and to combine the same with a steel facing extending across thefront face and side walls of the refractory so as to resist the erosiveaction of the material on the hearth against these portions of therabble.

Another object of the invention is to provide a coolant conductingpassageway for a rabble which is devoid of any obstructions therein tothereby insure a smooth flow of the coolant therethrough.

Another object ofthe invention is to utilize means associated with thecoolant conducting passageways to effect a better bond of the refractorymaterial with the said passageways.

A still further object of the invention .is to provide a rabble withcoolant conducting passageways associated therewith and wherein saidpassageways are formed of a plurality of straight tubular sections andreverse serve to conduct heat from the said side plates to the coolantconducting passage-ways.

Other objects and advantages of the invention will become apparentas thefollowing description of certain present preferred embodiments thereof aare hereinafter described.

DESCRIPTION OF THE DRAWINGS FIG. 1; is a sectional view taken throughone type of afurnace wherein baffles of the present. invention may beemployed.

FIG. 2 is aitopplan view of the rabble shown in FIG. 3 of the drawingsFIG. 32 is a perspective view of one form of rabble constructedinaccordance withthe present invention.

FIG. 4, is a sectiontakenon line 4 -4. of FIG. 3 looking in thedirection of the arrows.

FIG, 5 is a section ta kenon line 55 of FIG. 3, lookns: n, th d re t on.of the arr w FIG 6., is a top plan, view of the rabble shown in FIG. f te r w n FIG 7* is a perspective view of a modified form of rabbleconstructed in accordance with the present in cation of the rabbleconstructed accordance with the present invention.

FIG. 12 is a section taken on lines 12-1 of FIG. 11 of the drawings,looking in the direction of the arrows, and,

FIG. 13 is a section taken on lines 13-I3 of FIG. II, looking in thedirection of the arrows.

DESCRIPTION or THE PREFERRED EMBOD NT Referring now to the drawingswherein like numerals are employed to designate like parts throughoutthe several views, reference numeral designates a rabble and the mannerof constructing the same will be set forth with more particularityhereinafter.

The rabble of the present invention may be employed in furnaces havingdifferent hearth configuration. For instance, in Kemmerer et al. U.S.Pat. No. 3,475,286, which is incorporated herein by reference, there isshown therein rabbles which are roof supported and extend downwardly toa position in close proximity to a rotary hearth. In this prior patentthere is disclosed the employment of rabbles in association with aninclined hearth having a continuous sloping surface and a hearth formedof a plurality of concentrically arranged steps. The aforesaid patentdoes not show the rabbles in association with a flat hearth. However, itis pointed out the rabble of the instant invention can be as effectivelyemployed with a hearth formed of a horizontally extending flat surface.

The action of the rabbles in turning over and advancing the materialsonthe hearth progressively inwardly towards a central discharge pit isclearly shown and described in the aforesaid Kemmerer et al. patent.

The rabble of the present invention comprises a plowlike member of asubstantially flat formation having a circuitously arranged coolantconducting passageways 11 associated therewith. An inlet 12 and anoutlet 13 is provided as clearly shown in the drawings and the same areconnectedin any known manner to a suitable reservoir or header means(not shown) one such reservoir or header containing the coolant to befed to the inlet 12 of the passageways 11 and another reservoir or sumpfor receiving the coolant emerging from the exit end of the passageways.A suitable pump mechinism (not shown) is employed for forcing thecoolant fluid through the aforesaid passageways.

Referring now more particularly to FIGS. 2 to inclusive of the drawings,there is disclosed therein one type of rabble constructed in accordancewith the concept of the present invention. The rabble as shown in thesefigures of the drawings comprises a slanted bottom wall 14, a front face14 and side walls 15 and 16. This rabble is intended for use in afurnace having an inclined hearth.

However. in cases where the rabble is to be used in a furnace having aplurality of concentric steps or in a furnace having horizontallyextending flat hearth, the bottom wall of the baffle is not inclined asshown, but extends in a straight line from the aforesaid side walls 15and 16 so as to enable the same to plow or turn over the materials onthe stepped or flat hearth.

The rabble shown in FIGS. 2 to 5 inclusive of the drawings comprises aface plate 17 which extends throughout the height and width of therabble. The face plate may be constructed of steel or other metal foundsuitable to withstand the high temperatures within the furnace. Sidewalls 15 and 16 are likewise formed of steel or like metal and thesewalls may be formed integral with the face plate or secured thereto inany known manner as by welding, or the like. Thus, the rabble shown inFIGS. 2 to 5 inclusive of the drawings comprises what may be termed'abox-like structure with the back and top wall omitted. Mounted withinthe said box-like member are the passageways 11. Passageways 11preferably comprise one continuous conduit formed I in the shape of amodified W or if desired, the same generally at 18. Mounted on theconduits forming the passageways 11 are a plurality of steel clips 19which extend outwardly therefrom for a purpose to be more fullydescribed hereinafter. Also, a plurality of support bars 20 are spacedalong the inside walls 15 and 16, as

shown in FIGS. 2 to 5 of the drawings. To construct a rabble such asshown in these figures of the drawings, the'passagcways 11 formed asaforesaid are welded or otherwise secured to the face plate 17 of thebox-like member. Then, a suitable moldable refractory is placed withinthe aforesaid box-like member. The support bars 20 and clips 19 willengage with the refractory and when the same hardens, the bars and clipswill be embedded in the refractory and will serve to retain therefractory within the box-like enclosure. Also, the support bars 20which extend inwardly from the steel edges 15 and 16 will serve toconduct heat from these side walls to the coolant conducting passageways11. A rabble constructed as aforesaid is supported from the roof 22 ofthe furnace and the same is adapted to extend to a position in closeproximity to the moving hearth for the purpose previously described. Themounting of the rabbles in the roof of the furnace may be made inaccordance with the teaching of Kimmerer et al. U.S. Pat. No. 3,475,286,aforesaid, wherein the rabbles are adjustably supported in the roof sothat the same may be independently adjusted in their disposition withrespect to the hearth and the materials thereon so that they may bevaried as conditions dearound the passageways, the clips will beembedded inthe refractory to thereby assist in retaining the refractoryon to the passageways. The passageways 11 are provided with a coolantinlet 12 and an outlet 13, each connected to a suitable reservoir, asaforesaid. To construct a rabble such as shown in these figures of thedrawings, one need only to position the passageways 11 in a suitablemold and to thereafter fill the mold with a suitable refractory materialand allowed to harden. The clips 19 on the passageways 11 will assist inretaining the refractory material on to the aforesaid passageways. 1 7

Shown in FIGS. 10 to 13 inclusive of the drawings is a further modifiedform of the rabble. In these views of the drawings, the rabble comprisesa merely box-like member having a front face plate 17 and side walls 15and 16. The face plate and side walls are constructed of a suitablemetal and the same may be formed integral or the side walls may besecured to the face plate in any known manner as by welding, etc. Asdescribed with respect to FIGS. 2 to 5 of the drawings, the passageways11 are formed of one continuous conduit with portions thereof bent toform a modified W, or if desired, the same may be formed'ofa pluralityof straight and bent or curved sections joined together in any knownmanner. Clips 19 are mounted in any manner on the exterior of theconduits forming the passageways 11. Essentially, the rabble shown inFIGS. 10 to 13 inclusive of the drawings may be termed a cooled metalrabble. The passageways 11 are secured to the face plate 17 as bywelding 18 and the support bars 20 extending inwardly of the side walls15 and 16 and the clips l9 mounted on the conduits forming thepassageways will serve to extract heat from the immediate area of therabble and direct the same to the coolant conducting passageways. Inthis type of rabble, it has been found that the same may be constructedwithout the employment of a refractory as previously described, and therabble, by reason of the coolant conducting passageways in contacttherewith will function as intended, notwithstanding the excessivetemperatures to which the rabble is exposed.

The arrangement of the coolant conducting conduits in the manneraforesaid, provides for a larger surface area of the rabble to be cooledthereby, and a smooth flow of coolant therethrough is assured sincethere are no obstructions to retard the flow of the coolant.

The configuration of the passageways 11 has been described as being inthe shape ofa modified W. However. this shape is employed only toillustrate one form of configuration for the passageways. and it is tobe understood that a different configuration for the passageways couldbe equally as effective to provide for a properly cooled rabble. Thearrangement of the passageways. however. should be one wherein theconduits forming the same traverse the area of the rabble in a back andforth direction and be devoid of any obstructions which would impede theflow of coolant therethrough.

in the aforesaid Kemmerer et al. U.S. Pat. No. 3,475,286, the rabblesshown therein are employed to advance the materials on the hearth fromthe periphery thereof to a soaking pit which is located centrally of thefurnace. Obviously, the rabble of the present invention could be equallyapplied to a furnace wherein the materials to be processed therein arefed to the central portion of a hearth and caused to travel outwardly tothe periphery of the hearth for exit therefrom. As can be appreciated, arabble constructed in accordance with the present invention will enablethe fabrication thereof with a minimum of equipment. Actually,

all one needs to fabricate the rabble is the conduit, re-

fractory material and steel plate for the front and side walls. Thesimplicity of the arrangement of these components will enable one toassemble the same in the field or on site and the parts of the rabblewhich are subject to wear and abrasion can be readily replaced on sitewithout the necessity for complete replacement of the entire rabble.

The rabble has been described as roof supported. However. it is pointedout the rabble constructed aforesaid could be as equally effective inits intended purpose if the same is mounted within the furnace andretained therein by means other than the roof. such as a rabblesupporting arm extending within the furnace, or the like. Also, a liquidor a gas may be employed as the cooling medium for the rabble.

In the foregoing specification we have illustrated and described certainpresently perferred embodiments of our invention. However, it will beunderstood that this invention may be otherwise embodied within thescope of the following claims. I

What is claimed is:

l. A fluid cooled rabble comprising a plow-like member adapted to besupported from the roof of a furnace and extending to a position inclose proximity to a hearth within said furnace, said plow-like memberincluding a face plate, side walls, and a circuitously disposedsubstantially continuous piping extending along the said face plate, andside walls, said piping having an inlet and an outlet for a coolantcirculated therethr'ough.

2. The structure recited in claim 1 wherein said piping is secured tosaid face plate.

3. The structure recited in claim 1 wherein a refractory materialextends between the piping and said side walls.

4. The structure recited in claim 1 wherein said face and side wallscomprise metallic members.

5. The structure recited in claim 1 wherein said slowlike membercomprises a box-like member having a face and side walls and whereinsaid piping is secured to said face.

6. A fluid cooled rabble comprising a plow-like member adapted to besupported within a furnace with one end thereof extending to a positionin close proximity to a hearth within said furnace, said plow-likemember including a face plate, side walls. and a circuitously disposedsubstantially continuous tubing extending along the said face plate andside walls, said conduit having an inlet and an outlet for a coolantcirculated therethrough.

7. The structure recited in claim 6 wherein said tubing is secured tosaid face plate.

8. The structure recited in claim 6 wherein a refractory materialextends between the tubing and said side walls.

9. The structure recited in claim 6 wherein said face and side wallscomprise metallic members.

10. The structure recited in claim 6 wherein said slow-like membercomprises a box-like member having a face and side walls and whereinsaid tubing are secured to said face.

11. A fluid cooled rabble comprising a plow-like member adapted to besupported within a furnace with one end thereof extending to a positionin close proximity to a hearth within said furnace, said plow-likemember including a face plate, side walls, a circuitously disposedsubstantially continuous piping along the said face plate and sidewalls, clips mounted on said piping and support bars extending from thesaid side walls, said clips and said support bars assisting in thetransfer of heat from within the said rabble to the said piping.

12. The structure recited in claim 11 wherein said piping is secured tosaid face plate.

13. The structure recited in claim 11 wherein a refractory materialextends between the piping and said side walls.

14. The structure recited in claim 11 wherein said face and side wallscomprise metallic members.

15. The structure recitedin claim 11 wherein said plow-like membercomprises a box-like member having a face and side walls and whereinsaid piping are secured to said face.

16. A fluid cooled rabble comprising a plow-like member adapted to besupported within a furnace and extending to a position in closeproximity to a hearth within said furnace, said plow-like memberincluding a face plate, side walls, and a piping extending along andsecured to the said face plate, and side walls, said piping having aninlet and an outlet for a coolant circulated therethrough.

17. The structure recited in claim 1 wherein said piping is secured tosaid face plate.

18. The structure recited in claim 1 wherein a refractory materialextends between the piping and said side walls.

v 19. The structure recited in claim 1 wherein said face plate and sidewalls comprise metallic members.

20. The structure recited in claim 1 wherein said plowlike membercomprises a box-like member having a face plate and side walls andwherein said piping is selcured to said face plate.

1. A fluid cooled rabble comprising a plow-like member adapted to besupported from the roof of a furnace and extending to a position inclose proximity to a hearth within said furnace, said plow-like memberincluding a face plate, side walls, and a circuitously disposedsubstantially continuous piping extending along the said face plate, andside walls, said piping having an inlet and an outlet for a coolantcirculated therethrough.
 2. The structure recited in claim 1 whereinsaid piping is secured to said face plate.
 3. The structure recited inclaim 1 wherein a refractory material extends between the piping andsaid side walls.
 4. The structure recited in claim 1 wherein said faceand side walls comprise metallic members.
 5. The structure recited inclaim 1 wherein said slow-like member comprises a box-like member havinga face and side walls and wherein said piping is secured to said face.6. A fluid cooled rabble comprising a plow-like member adapted to besupported within a furnace with one end thereof extending to a positionin close proximity to a hearth within said furnace, said plow-likemember including a face plate, side walls, and a circuitously disposedsubstantially continuous tubing extending along the said face plate andside walls, said conduit having an inlet and an outlet for a coolantcirculated therethrough.
 7. The structure recited in claim 6 whereinsaid tubing is secured to said face plate.
 8. The structure recited inclaim 6 wherein a refractory material extends between the tubing andsaid side walls.
 9. The structure recited in claim 6 wherein said faceand side walls comprise metallic members.
 10. The structure recited inclaim 6 wherein said slow-like member comprises a box-like member havinga face and side walls and wherein said tubing are secured to said face.11. A fluid cooled rabble comprising a plow-like member adapted to besupported within a furnace with one end thereof extending to a positionin close proximity to a hearth within said furnace, said plow-likemember including a face plate, side walls, a circuitously disposedsubstantially continuous piping along the said face plate and sidewalls, clips mounted on said piping and support bars extending from thesaid side walls, said clips and said support bars assisting in thetransfer of heat from within the said rabble to the said piping.
 12. Thestructure recited in claim 11 wherein said piping is secured to saidface plate.
 13. The structure recited in claim 11 wherein a refractorymaterial extends between the piping and said side walls.
 14. Thestructure recited in claim 11 wherein said face and side walls comprisemetallic members.
 15. The structure recited in claim 11 wherein saidplow-like member comprises a box-like member having a face and sidewalls and wherein said piping are secured to said face.
 16. A fluidcooled rabble comprising a plow-like member adapted to be supportedwithin a furnace and extending to a position in close proximity to ahearth within said furnace, said plow-like member including a faceplate, side walls, and a piping extending along and secured to the saidface plate, and side walls, said piping having an inlet and an outletfor a coolant circulated therethrough.
 17. The structure recited inclaim 1 wherein said piping is secured to said face plate.
 18. Thestructure recited in claim 1 wherein a refractory material extendsbetween the piping and said side walls.
 19. The structure recited inclaim 1 wherein said face plate and side walls comprise metallicmembers.
 20. The structure recited in claim 1 wherein said plowlikemember comprises a box-like member having a face plate and side wallsand wherein said piping is secured to said face plate.